1. Field of the Invention
The present invention relates to a transmission device for an electric cycling exerciser.
2. Description of the Related Art
Besides poor blood circulation, the body of a person that has sat for hours would become stiff and the person would feel tired. An electric cycling exerciser is provided to exercise the user""s legs while the user is sitting or lying down on the floor, thereby improving the blood circulation. FIG. 11 of the drawings illustrates a conventional electric cycling exerciser comprising a motor 1xe2x80x2 having an output shaft 11xe2x80x2, a gear 2xe2x80x2 meshed with the output shaft 11xe2x80x2 of the motor 1xe2x80x2, and two pedals 3xe2x80x2 operably connected to the gear 2xe2x80x2. When the motor 1xe2x80x2 is turned on, the pedals 3xe2x80x2 are turned. Nevertheless, such an electric cycling exerciser has the following drawbacks. First, when the user""s foot has not yet firmly stepped on the respective pedal 3xe2x80x2, the user""s foot would fall and thus be injured by the turning pedal 3xe2x80x2. The injury is more serious if the foot is stuck, as the motor 1xe2x80x2 keeps running. Secondly, if the user""s foot steps on the respective pedal 3xe2x80x2 with a greater force or drives the respective pedal 3xe2x80x2 in a reverse direction, this would feed back to the motor 1xe2x80x2 such that the motor 1xe2x80x2 could not drive the gear 2xe2x80x2 and the respective pedal 3xe2x80x2 in a normal condition. As a result, the temperature of the motor 1xe2x80x2 would rise and thus cause damage to the motor 1xe2x80x2.
An object of the present invention is to provide a transmission device for an electric cycling exerciser, the transmission device having a safety member to avoid injury to the user""s foot.
In accordance with a first aspect of the invention, an electric cycling exerciser comprises:
a housing;
a shaft rotatably mounted to the housing;
two pedals respectively operably attached to two ends of the shaft;
a motor; and
a gear rotatably mounted on the shaft and driven by the motor, the gear including a safety member rotatably mounted therein, the safety member being fixed to the shaft to turn therewith, one of the gear and the safety member including at least one groove for receiving an elastic element and an insert, the other of the gear and the safety member including at least one insertion groove for receiving the insert, the insert being biased by the elastic element into said at least one groove, thereby allowing joint rotation of the gear and the shaft;
wherein when a user""s foot is stuck between a respective pedal and the housing or the respective pedal is subject to a force greater than an engaging force between said at least one insertion groove and the insert, the insert is disengaged from said at least one insertion groove such that the shaft and the safety member are not turned while the gear is being turned.
In accordance with a second aspect of the invention, an electric cycling exerciser comprises:
a housing;
a first shaft rotatably mounted to the housing;
a second shaft rotatably mounted to the housing;
two pedals respectively operably attached to two ends of one of the first shaft and the second shaft;
a motor; and
a gear train including at least a first gear mounted to the first shaft and a second gear mounted to the second shaft, the first gear being meshed with the second gear, one of the first gear and the second gear being driven by the motor;
one of the first gear and the second gear including a safety member rotatably mounted therein, the safety member being fixed to an associated one of the first shaft and the second shaft to turn therewith, one of said one of the first gear and the second gear and the safety member including at least one groove for receiving an elastic element and an insert, the other of said one of the first gear and the second gear and the safety member including at least one insertion groove for receiving the insert, the insert being biased by the elastic element into said at least one groove, thereby allowing joint rotation of said one of the first gear and the second gear and an associated one of the first shaft and the second shaft;
wherein when a user""s foot is stuck between a respective pedal and the housing or the respective pedal is subject to a force greater than an engaging force between said at least one insertion groove and the insert, the insert is disengaged from said at least one insertion groove such that the safety member and an associated one of the first shaft and the second shaft to which the pedals are mounted are not turned.